Violence raged in Syria's second city Aleppo overnight and into Wednesday morning, as regular troops battled rebels forces, the Syrian Observatory for Human Rights said.

Violence raged in Syria's second city Aleppo overnight and into Wednesday morning, as regular troops battled rebels forces, the Syrian Observatory for Human Rights said.

The Britain-based watchdog reported clashes in the district of Bustan al-Qasr in the south of the city, and said government forces used helicopter gunships to strafe neighbourhoods, causing deaths and injuries.

Fighting was also reported in the central Al-Jamaliya neighbourhood, close to the local headquarters of the ruling Baath party.

In Aleppo province, the army battled to retake the rebel town of Al-Bab, shelling the area as it tried to reclaim it.

Elsewhere in the country, security forces continued to fight with prisoners at the central prison in Homs, after a mutiny that saw detainees take over a wing.

The Observatory said security service agents and regular troops took part in the operation, which left "dead and wounded."

Elsewhere in the central city - Syria's third largest - a rebel fighter was shot and killed by a sniper in the Al-Qarabis district, the group said.

Further north, in Hama province, 16 people were killed in an army assault on the village of Sharia, while two children were killed in dawn shelling of the town of Karnaz.

In the northwestern province of Idlib, shelling killed four civilians in the town of Kfar Roma, the Observatory added.